Adult emerald ash borer beetles will lay their eggs only on ash tree bark.
It’s got a voracious appetite and takes no prisoners. The emerald ash borer is being taken seriously by natural resource managers because it has the potential to kill 7.5 billion ash trees throughout North America, according to the U.S. Forest Service.
The iridescent, metallic green beetle made its unwanted debut in 2002 in southeast Michigan, where it is thought to have arrived in wooden packing crates from Asia. Since they have no natural predator, the beetles have marched through Michigan, into Ohio, Indiana, Illinois, West
Virginia and Pennsylvania. Possible contamination through firewood extends to Maryland, New York, Wisconsin and Missouri.
The beetles choose only ash trees to complete their life cycle. Adult beetles lay their eggs in the bark and the larvae burrow into the tree after hatching. The larvae feed on the inner cellulose tissue that serves as the transport system of food and water for the tree. Eventually, the larvae girdle the tree and kill it—a process that takes three to four years. The larvae emerge from the tree when they reach adulthood, just 1⁄2" long, leaving a D-shaped opening in the bark.
Slowing their spread entails finding the beetles in order to quarantine infected areas. To do this, plastic, purple birdhouse-looking traps are mounted on poles in woody areas near the infected counties to serve as presence alarms.
Therese Poland, an entomologist with USDA Forest Service, claims that this color and a shade of light green get the biggest response from the beetles.
"The beetle is attracted to volatile oils released from the green leaves of ash trees as well as odor compounds from ash tree bark," Poland says. The traps are baited with these oils.
Farmers can help by making sure cut firewood is used and sold locally. Contact your state department of agriculture or natural resources office if you see emerald ash beetles or damage to ash trees. For more, go to www.emeraldashborer.info.
- January 2012